This paper argues that two serious flaws are present in current mathematics learning and instruction: (1) the lack of meaning in students' mathematical knowledge; and (2) students' inability to communicate using appropriate mathematical language and ideas. The study explored the relationship between mathematics language facility and mathematics achievement. Written tests in mathematics language and mathematics achievement were administered to 177 junior high school students. Results of ANOVAs indicated three groups in the sample: average minority, average majority, and above-average students. Multiple regression analyses showed that, for both average groups, the "interaction" of language facility and procedural knowledge significantly predicted conceptual achievement. For above-average students, language facility and procedural knowledge each significantly predicted conceptual achievement. The relationship was further explored by comparing conceptual achievement means for combinations of high and low performance in mathematics language and procedures. Results clearly illustrated the interaction between language and procedure for both average groups. For above-average students, the additive effects of the two predictors were evident. A 50-item reference list is included. (Author/PK)